I put this together recently, and think the basic research I've done so far would benefit from more technical users who are interested poking around with it. At any rate, the tut is up on the wiki, and reproduced below as well. It's written for a non-MATY audience, so please don't feel condescended to that it assumes you might not know some basic stuff. Do let me know of any errors, major or slight:

It is possible, using a combination of mods and EA debug commands, to add Sims to custom worlds using Edit-In-Game in the Create-A-World tool (CAW). Testing to date demonstrates that these Sims will be installed with the world file, and will act just as the premade Sims in Sunset Valley or Twinbrook. '''However''', creators should bear in mind the pool of testers has been small and largely non-technical. These testers have now maintained working worlds across four or five generations without any corruption that is apparent to end users. Suffice to say, worlds populated with this method should carry warnings, but appear to be safe if certain rules are followed. Even so, it is a sensible precaution to back up the world before attempting this.

This tutorial assumes readers understand how to install and manage custom content.

Requirements

Required Mods

awesomemod

NRaas DebugEnabler

Strongly Recommended Mods

NRaas Porter

NRaas SuperComputer

Players can find the latest version of awesomemod ... here. Obviously.

(If you are reading this during the Great CAW Famine of 2010 and have rolled back the patches, you'll want the 1.11 version of twallan's mods in his Obsolete Mods thread).

Drawbacks

This method has some drawbacks in terms of which Sims creators can and cannot add to their worlds. For example, Ghosts and Mummies added in Edit-In-Game lose some of their essential data during saving, specifically the data from when they were normal Sims. Hence Ghosts and Mummies always become hopelessly corrupted. Likewise, urns containing dead Sims are stripped of their Ghosts, and will present simply as "Remains" objects. Players seeking to incorporate Ghosts and occult Sims into their worlds must offer these Sims in a shared save file - there is no other way. This corruption more than likely also affects SimBots because unfortunately they also carry the data that would allow them to turn into normal Sims, even though there is no way for them to do so in the vanilla game.

Aside from this, Sims should not have complex relationships with objects, nor pre-existing skill data if they are imported with the Porter mod. Do not important Sims that have written books, painted paintings, or made nectar bottles, etc. There is a good chance these objects, if also imported, will corrupt. There is also a chance the Sim's skill data will not save in its entirety. Creators should keep the Sims they import clean and simple - preferably fresh from Create-A-Sim or Create-A-Family. Set all skill levels with the SuperComputer mod once the Sims are in Edit-In-Game mode. Bear in mind at all times that not all processes run in Edit-In-Game mode, and there is the risk that any but the most basic data won't transfer into this environment, or be preserved in CAW more generally.

Do not ever let a Sim die in CAW. It never turns out well, and often crashes the entire programme. The NPC household doesn't exist in Edit-In-Game, so there's no Grim Reaper, and this mode doesn't run death scenarios properly. You'll just corrupt Sims. ''Force Kill'' with SuperComputer is not a way around this. It just results in Urns with heavily corrupted Sims attached.

Basic Method

Not all the advice that follows is essential to getting Sims into a world, but it is all worth knowing to do a good job of it.

Step One: Using the Make Sim command in Edit-In-Game

Lots are an essential requirement. They are the vessels that carry all a creator's Sims and their data. First, the creator should '''finish''' their world, excepting only small details like the odd bush or street lamp. This is a precaution to ensure the Sims' data is preserved perfectly, without any risks that might arise from building upon or shifting lots with Sims in them. Creators can risk it if they want, but it is not recommended. Before adding Sims it might pay to switch the Story Progression toggle off, as while the Sims only seem to do basic processes and have static motives, awesomemod's story progression could possibly interfere with the world's compatibility in unmodded games.

All the action takes place in Edit-In-Game mode, so once the world is ready, enter it. The player must type ''setconfig EnableDebugInteractions true'' into the cheat console once the world has loaded. This unlocks a limited selection of EA debugging interactions when Shift-Ctrl-clicking on the terrain.

The same interactions are unlocked with NRaas DebugEnabler, simply type Make Sim into the cheat console and you will have an active homeless Sim. (This is the best method for making homeless Sims for your world).

The ''Make Sim'' interaction spawns a random EAxis pudding-faced Sim attached to a nearby residential lot. It is best to spawn them on a specific lot, which simply means running ''Make Sim'' on that lot's terrain. This Sim automatically becomes the player's active household and active Sim, just like when playing the game. Sims in Edit-In-Game have no free will, and their motives are static (don't worry, they don't remain static in the actual game). They can run around town, and interact with most objects, but bear in mind they will ''always'' be standing up when the player first opens the game, so sitting them in a chair or on a bed will result in upright Sims clipping weirdly through the objects. The random Sim I've been saddled with is Gregg Edward. For a random Sim he's surprisingly unfugly, but this process is totally as random as the EAxis townie spawning in the game, so most of the time these Sims will look ridiculous. At any rate, players should now have a Sim standing about on a lot in Edit-In-Game, and under their control.

This Sim is a powerful tool, unlocking many more commands that, without an active Sim, are not available. However, creators should use the additional debugging commands with extreme caution, if at all, and if you do not know what a command does DO NOT TOUCH IT.

Step Two: De-fuglying and clean up

This step is where NRaas SuperComputer comes in handy, although not essential. If creators want only to make Sims and then de-pudding them, dress them properly, change their traits and wishes, and add description text then awesomemod is sufficient. Just use the ''editsim'' cheat that awesomemod provides (eg. ''editsim Gregg Edward''). Spawn each new Sim on the lot you wish them to inhabit using ''Make Sim''. However, if creators want a population of inter-related Sims with varying careers and skill levels, it pays to also have SuperComputer installed. Do not try to use the EA debugging commands to set skills and careers: SuperComputer is safer and more reliable. Players who have used SuperComputer previously will have no trouble with this, and for players unfamiliar with the mod it is very intuitive. It should not pose any steep learning curve, and twallan provides further instructions on his forums.

Creators can edit family descriptions from Edit Town mode, but should not try switching or moving active families here. This will deselect the current household. Instead use SuperComputer's ''Add Sim'' command to move Sims from on household to another. Without an active Sim, creators cannot select other Sims, so it is necessary to use ''Make Sim'' at the beginning of every session in Edit-In-Game. For this reason, it is best to try and add all the Sims to a world in one session (step three will be helpful in this regard). Any excess Sims can be destroyed cleanly using SuperComputer's ''Total Annihilation'' interaction, or awesomemod's ''Nuke'' interaction.

Pregnancies set with SuperComputer's ''Pollinate'' command will carry over successfully into the world you create.

Step Three: How to add premade Sims

When the creator discovers that CAW blocks access to Create-A-Family in Edit-In-Game, and that all the accessible manifestations of Create-A-Sim don't allow access to premade Sims, they can start to see a horrifying one-by-one effort of sculpting and resculpting every single Sim in the entire world individually. Forever.

There is, after all, not even access to the genetic mixing tool for making children. The outlook is bleak until the creator discovers that twallan's Porter mod also works in Edit-In-Game so long as they have an active Sim in the world. Porter allows creators to add families from the family bin into lots simply by clicking on the lot, selecting ''Porter'' and choosing the name of the family in the bin. For this reason, it helps to keep the family names distinct from one another - creators can always change them using Edit Town mode once they're in Edit-In-Game. So it's simply, really: Build all the families in the game itself, save them to the bin, and then introduce them into Edit-In-Game using ''Make Sim'' > ''Porter'' > ''[Family name]''.

Before saving there is one essential step that the creator must take using NRaas DebugEnabler. Sims' motives are calculated in accordance with the time in the world. More than likely the creator has let the clock run in Edit-In-Game, and this can cause an intial lag on when the motives begin to calculate for players who have just loaded up the world. Thank twallan of NRaas for providing a specific solution to this issue. Using DebugEnabler, and making sure the game is paused, type in the '''restartmotives''' command. Now save the game, without letting the clock run again. This ensures that all Sims' motives will start calculating as soon as the world is loaded. If you adjust the world in any way that lets the clock run, remember to redo this step before saving.

Step Five: Narrative tricks

But what is this all in aid of? If a player is adding Sims to their world it is because they want the place to have a sense of history, and greater sense of ''lived-in-ness''. So it is worth taking time to discuss different narrative tricks that are available. But first, let's look at the constraints with this method.

Constraints

- No deceased Sims, so all relatives must my living.

- No active Mummies, Ghosts, or SimBots

- No sims sitting or lying on objects when the world first loads

- No skilling history that isn't added with SuperComputer

Pregnancies

- Adding pregnancies is a great way to ensure a few more non-pudding faced Sims will start out in the world, adds a bit of randomness to families (pregancies are always concealed at the world's launch, except for morning sickness). It adds to the ever important sense of history, and can leave players speculating about patternity as in Claire Ursine's case.

Adding Moodlets

- This is a fantastic, if fiddly, feature of EA's debug commands. Once you have this unlocked, simply select a Sim you've added to the world, and use the ''Add Buff'' command. This will give you a list of all the possible moodlets. You can have a grieving Sims (but because no Sim has actually died the moodlet will be neutral, although the Sims will still cry), Sims that have just eaten Ambrosia (back from the dead?), Sims that have just time-travelled! In my version of Riverblossom Hills I placed a broken, rusty TV beside my mad professor, and have her starting the game Singed. Remember that moodlets like Singed actually cause the Singed state! The possibilities for how your Sims begin their lives with players is very broad here.

- It's possible to make Sims that are about to die. Give a Sim the 'On Fire' or 'Mummy's Curse' moodlet, and the player will have to choose whether they save them or not. Time can pass in Edit-In-Game, so you can even run the moodlet down if you're patient. Just don't ever let the Sim die in Edit-In-Game this will either crash the whole programme, or it will result in a corrupted Sim that will NEVER die (this isn't a good thing, the Sim is corrupted, not enhanced, and will mess up player's games. Don't make the mistake of using glitches as part of your narrative!) You can also set Elder's ages very high using SuperComputer, guaranteeing they will die soon after the world first launches. This can help if you want families to have dead Sims in their family trees relatively swiftly - a sense of generations passed.

Positioning

- Sims can leave their lots. Remember that if a Sims starts somewhere far from their lot it could leave players quite confused as to where their home is, but this can be useful for placing one or two Sims from a large family somewhere interesting. For example, the world might launch with a teen Sim meeting his girlfriend in the park while his family are at home. Appropriate moodlets on the two teen sims in the park helps deepen and clarify the player's experience.

If you read this far and didn't just click the links above: *slow clap*